Historically, explosive-filled ordnance such as mines and hidden explosive devices have proven to be a significant obstacle to be overcome in both low and high intensity conflicts. Mines and hidden explosive-filled ordnance destroyed over 25 percent of the vehicles lost in World War II, a percentage that almost tripled in the Viet Nam War. Because of the continued improvement in flexibility, sophistication, kill power, ease of use and effectiveness of such mines, the potential for the continued use of such mines and hidden explosives for area denial and barrier munitions will continue to play a vital role in successful defensive tactics.
Current explosive-filled ordnance neutralization techniques include plows, rollers or flails attached to the front of an armored vehicle, as well as projected explosive charges. One such technique is illustrated in U.S. Pat. No. 3,771,413 issued to Sieg et al. The mine neutralization device of this type employs wheels which are mounted on the vehicle, such as a tank, and are utilized to neutralize; i.e., detonate pressure actuated land mines buried in the ground which are in the vehicle's path of travel. Such neutralization techniques are rarely used until the presence of a mine field is established; and once established, these techniques are slow and vulnerable to covering fire. A mine field protected by covering fire can be extremely difficult to breach. Further, some of the mines in the mine field may be missed because of the use of an advanced fuze system or the use of infrequent individual mines.
The range clearance system set forth in U.S. Pat. No. 4,449,239 issued to Pedersen illustrates a method of clearing a target range or other areas such as a war zone of buried unexploded ordnance by enhancing oxidation of ferrous ordnance in situ. This method advances the natural galvanic electrochemical corrosion whereby ferrous parts of the unexploded ordnance are simply rusted away at an accelerated rate and rendered harmless within five to ten years. However, while such a system may be effective in clearing a target range for future use, this system is both impractical and unusable where it is desired to quickly and effectively clear explosive infested areas such that troops or other personnel may readily occupy the previously infested area.
Various other techniques have been employed to neutralize explosive devices. Examples of such are set forth in U.S. Pat. No. 4,046,055 issued to McDaniels et al. and U.S. Pat. No. 3,800,715 issued to Boller. Each of these devices employ the use of liquid nitrogen to cool the device to a temperature at which the device becomes inoperative. One such device requires penetrating the individual casing of the unexploded ordnance with the subsequent injection of liquid nitrogen into the device. With the device of Boller, an unexploded ordnance is drawn into an open-ended tubular shell which is then filled with liquid nitrogen to freeze the bomb to deactivate the explosive material contained therein. However, each of these devices is used to merely deactivate a single bomb and cannot readily or safely be used to neutralize unexploded ordnance scattered over a large explosive infested area. Remote clearing of mine fields from a distance may also be carried out by the use of projected explosive charges which can quickly clear paths. This procedure; however, requires large amounts of explosives and causes large airblasts which are often undesirable. Moreover, this procedure is often only effective in detonating single-impulse pressure mines. Consequently such a procedure may not reliably clear the unexploded ordnance infested area.
Clearly, there is a need for both a system and method for readily neutralizing unexploded ordnance and clearing explosive infested areas such that maneuvers may be continued in a rapid and a confident manner. Further, such neutralization and clearing must be capable of being carried out safely with the unexploded ordnance being continuously maintained in an inert state.